Means for distributing viscous substances on falling film evaporators



Get. 16, 1962 K BRUNK 3,058,516

MEANS FOR DISTRIBUTING VISCOUS SUBSTANCES 0N FALLING FILM EVAPORATORSFiled April 1, 1958 2 Sheets-Sheet 1 K ONRAD BRUNK A TTORNE Y8 Oct. 16,1962 K. BRUNK MEANS FOR DISTRIBUTING VISCOUS SUBSTANCES ON FALLING FILMEVAPORATORS 2 Sheets-Sheet 2' Filed April 1, 1958 Q. "Ii..il

INVENTOR.

KONRAD BRu/vK 3% ATTQRNEYS United States Patent MEANS FOR DISTRIBUTINGVISCOUS SUB- STANCES 0N FALLING FILM EVAPO- RATORS Konrad Brunk,Leverkusen, Germany, assignor to Farbenfabriken BayerAktiengesellschaft, Leverkusen, Germany, a corporation of Germany FiledApr. 1, 19:53, Ser. No. 725,743 Claims priority, application GermanyApr. 5, 1957 6 Claims. (Cl. 159-6) The distributors hitherto usuallyemployed in thin-' layer evaporators consist of brushes, wiper blades,doctors or scrapers, which are arranged on a shaft rotating in theevaporator body and slide on the inside wall of the latter or sweep pastclose alongside the same. The fine dust being formed with rubbing orsliding distributor elements enters into the substance being processedand contaminates the latter, this being undesirable in many cases. Whenhighly viscous pasty or like masses are introduced into the thin-layerevaporator, the aforementioned distributor devices which have so farbeen employed can only be used under certain circumstances, since it isfrequently not possible to obtain with them a uniform distribution ofthese viscous masses on the inside wall of the evaporator.

It has now been found that the said disadvantages are avoided if thedistributor device consists, in accordance with the invention, of atleast one roller which is rotatably mounted in cross-members connectedto the shaft and in addition is preferably movable radially in slots ofthe cross-members, so that it rolls on the inside Wall of the evaporatorchamber owing to centrifugal force as the shaft rotates and thusdistributes the product to be processed. Since the roller rotates, therubbing action is neglig ly 211, 50 that Contamination of the substancebeing treated is practically avoided. Finally, the roller can also be soarranged, for example by stop devices, that it is stopped at a certaindistance from the inside wall.

By using such rollers, not an thin liquid but especially also veryviscous masses can be satisfactorilyrolled out on the inside wall toprovide a thin film. The use of the distributor according to theinvention also provides an increase in the evaporator surface and thusan increase in the evaporator output, since as the rollers rotate, someof the substance to be treated is also taken up on the surface of thesaid rollers. In order fully to utilize this increase in surface, therollers are provided with an internal heating system. In order incertain cases to obtain a positive or negative slipping of theirsurfaces on the inside wall, the rollers are provided with anindependent driving means. In order to allow the rollers to roll on thewall of the container with a pressure exceeding the centrifugal force,they are provided with a supplementary pressure device, for example aresilient pressure device.

The construction of the distributor device can be varied in many ways,depending on the number and diameter of the rollers and also thearrangement and shape thereof. For example the rollers can be made ofthe same length as the length of the evaporator which is to be sweptover.

The rollers, especially when they are of small diameter, can be mountednot only at the top and bottom, but once or several places along theirlength.

Several separate rollers of shorter length can be arranged in series oradjacent one another.

The rollers can be of conical shape instead of being of cylindricalform.

The rollers can be shaped, for example provided with spiral threads.

In order to produce a thrust action in a downward di- Patented Oct. 16,1962 ice 2 motion on the product to be treated, the rollers can bearranged with their central axis inclined to the central axis of theevaporator and they are then given for example an ellipsoid form.

Embodiments of the device according to the invention are showndiagrammatically and by way of example in the drawing. FIGURE 1 is alongitudinal section through an evaporator body having distributorrollers for thinly liquid and thickly liquid substances. FIGURE 2 is across-section through this apparatus, FIGURE 3 is a longitudinal sectionthrough an evaporator with a distributor device which is particularlysuitable for highly viscous pastry substances. FIGURE 4 shows aconstructional example of an internally heated roller, FIGURE 5 shows aroller with its own driving means, FIGURE 6 shows a roller with a springpressure device and FIGURES 7 and 8 show a distributor device havingrollers arranged inclined in relation to the evaporator axis.

Referring to the constructional example illustrated in FIGURES l and 2,the reference 1 represents the everorator chamber with the heatingjacket 2. Arranged in the evaporator 1 is the driving shaft 3 with thecrossmembers 4 fixed thereon, the rollers 6 being rotatably mounted bymeans of their journals 7 in the slots 5 of said crossmeinbers. Theinlet tube for the material to be treated in indicated at 8. As theshaft 3 and thus the cross-members 4 rotate, the rotatably mounteddistributor rollers 6, are. urged by the centrifugal force on to theinside wall of the evaporator 1 and on to the substance supplied throughthe pipe 3 and flowing down on said wall, he" ol er te l n 1 he s bs nceand d st i u i g it uniformly on the wall surface by rolling it out in athin a e n, t Said ll- The a a ge en how in FIGURE 3, which is moreespecially suitable for distributing viscous substances which no longerare able to ssii iilyw h e f ce at r i y w ng o the r a es n power, alsoconsists of the evaporator casing 1 with the heating jacket 2, thecross-members 4 of the shaft 3, the rotatably arranged rollers 6 and asupply pipe 8 for the a er aln t is a e. owev a p qpe le m m 9 formed ofa spiral two-thread worm of flat sheet metal blading is additionallyarranged on the shaft 3 so that about two thirds of the length of theworm is above and one third is below the supply pipe 8 and that thelower ends of the Worm threads extend to between the upper ends of thedistributor rollers 6. This propeller member 9 urges the materialdownward-1y on the evaporator surface and away from outlet 10 andprevents any doughy viscous product forced into the apparatus fromdamming up in the space above the rollers. The evaporator casing 1 isequipped with an outlet pipe 10 for the distillate vapours and an outletpipe 11 for the residue. The shaft 3 is guided through the cover 12 ofthe evaporator casing 1 and carries at its end a driving pulley 13. Thepassage for the shaft through the cover 12 is sealed by means of astufiing box. According to FIGURE 4, the roller is made hollow and isrotatably mounted on the hollow angle piece 16 of the hollowcross-member 17. Fixed to the journal of the angle piece 16 is a heatingelement 18 which serves to heat the interior of the roller 15. The leads19 for supplying the heating current are led outwardly through thehollow part of the shaft 20 to slip rings.

FIGURE 5 shows a distributor roller with a separate or individualdriving means. In this figure, 21 represents the internal wall of theevaporator, 22 the supply opening for the product to be treated, 23 thedischarge pipe for the distillate vapours, 24 the main driving shaft, 25an internally toothed crown wheel which is fixed to the collar 26, 27 isa bushing which is connected fast to the shaft 24 and which is providedat the upper end with a disc 27a and at the bottom end with across-member 27b forked at its ends, 28 is a gear wheel mounted in thedisc 27a and having a pinion 28a which meshes with the crown wheel 29 isan intermediate pinion mounted in the disc 27a, 30 is the driving pinionfor the roller and mounted in the disc 27a, 31 is the roller with itsupper bearing journal 31a, 33 are blocks sliding in the forks of thecross-member providing bearings for the journals of the rollers 31, and34, 35 and 36 are articulated shaft connections between the pinion 30and the roller journal 31a.

When the main driving shaft 24 rotates, the pinion 28a rolls on thecrown wheel 25, from which the rotational movement is transmittedthrough the gear wheel 28 and the pinions 29 and 30 by means of thearticulated shaft connections 34, 35, 36 to the rollers 31. Depending onthe transmission ratio chosen for the gearing, the peripheral speed ofthe roller is equal to, larger than or smaller than the peripheral speedof a point around the shaft 24 at the distance of half the diameter ofthe evaporator space, i.e. the surface of the roller either has no slip,or a positive or negative slip, relatively to the inside wall of theevaporator. A displacement of the rollers, which is necessary whendistributing the productwhich is to be treated, is obtained by mountingthe rollers in blocks sliding in the forks of the cross-members.

According to FIGURE 6, the rollers 38 rolling on the wall of thecontainer 37 have their ends mounted in sliding members 39 and areforced by means of the leaf springs 40 against the wall 37 by means ofthe sliding blocks 39 displaceable in the cross-members 41.

A distributor device having rollers arranged at an inclination to themeans axis is shown in FIGURES 7 and 8 and therefore having anelliptical profile.

In these figures, 42 is the driving shaft, 43 is the upper and lowercross-members connected fast to the shaft 42, 45 are the convex inclinedrollers movably mounted in the forked ends of the cross-members, 46 isthe wall of the evaporator space and 47 is the supply pipe for theproduct.

As the shaft rotates in the direction indicated, the product to beprocessed is given a downward thrust by the rotating inclined rollersand this assists the action of the force of gravity.

I claim:

1, An evaporator comprising an evaporator chamber 4 having an inlethaving material to be treated and an outlet for withdrawal of vapor,roller means below said inlet and adapted to spread said material thinlyon the inner wall of said chamber, and propeller means within saidchamber extending from said inlet below said roller means to advancesuch material thereto.

2. An evaporator as set forth in claim 1 in which said roller meansincludes at least one roller urged by centrifugal force in the directionof said chamber inner-wall.

3. An evaporator as set forth in claim 1 in which said propeller meansincludes spiral blading adjacent the inner wall of said chamber.

4. An evaporator as set forth in claim 1 in which said propeller androller means are rotatable about the center of said chamber.

5. An evaporator as set forth in claim 4 in which said chamber isprovided with a central vertical rotatable shaft and said propeller androller means are adapted to be rotated in said chamber by said shaft.

6. An evaporator comprising a cylindrical evaporator chamber having aninlet for material to be treated and an outlet for withdrawal of vapor,a central vertical shaft, a plurality of rollers mounted for rotationupon and by said shaft, and adapted to be urged by centrifugal forcetoward the inner wall of said chamber and to spread said material thinlythereon, spiral blading carried by said shaft and rotatable therewith,adjacent the inner wall of said chamber and extending above said inletsubstantially two-thirds of the overall length of the blading and abovesaid inlet to propel said material from the inlet to said rollers.

References Cited in the file of this patent UNITED STATES PATENTS1,284,974 Du Pont Nov. 5, 1918 1,895,740 Ukropina Jan. 31, 19332,032,785 Zorn et al Mar. 3, 1936 2,306,496 Petersen Dec. 29, 19422,460,602 Semon Feb. 1, 1949 2,500,900 Madlen Mar. 14, 1950 UNITEDSTATES PATENT OFFICE v CERTIFICATE OF CORRECTION Patent No. 3,058,516October 16,

Konrad Brunk Column 2, line 13, for "pastry" read pasty column 4, line37, for "1,284,974 Du Pont" read 1,28%074 du Pont Signed and sealed this7th day of May 1963.

(SEAL) Attest:

ERNEST w. SWIDER DAVID L- LA Attesting Officer Commissioner of Patents

